Operating stresses in aircraft-engine crankshafts and connecting rods 2: instrumentation and test results Page: 3 of 24
This report is part of the collection entitled: National Advisory Committee for Aeronautics Collection and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
NACA AM .No. 35H18
vibration of the shaft, however, cannot be determined, from torsional-
vibration data. WHire strain gages have therefore been used for
measurement of bending vibration (reference 1).
No literature on the measurement of operating stresses in con-
necting rode of high-speed engines has come to the attention of the
authors. The importance of investigating vibration conditiore in
connecting rods has been recognized but, because suitable instrumen-
tation and methods were lacking, experimental strain-measurement
investigations have not been made heretofore.
The instrumentation and methods that were used to measure
stresses in the crankshaft and the master connecting rod of a modi-
fied test engine are described herein and the test results are pre-
sented. Wire strain gages were employed for the measurement of dy-
namic strains in the crankshaft and the master connecting rod. Strain
gages mounted and used as described yielded an over-all strain sig-
nal of relatively large amplitude, which minimized the effect of
distortion caused by slip rings and high-gain amplifiers.
DESC2.IPTIBI 09 AP2ADATUS
Test Engine
The strain-measurement invostigatioa was conducted on an air-
craft engine that had be"n converted to a three-cylinder test en-
gine. The mPster-rod cylinder (Fo. 1) was operae.te d under power,
whereas cyline.ers -and 7 were motored with exhaust and intake
valves installer but with valve push rods removed. The power was
absorbed by an electric dynamometer. In all tests, standard labo-
ratory equipment was used to measure engine speed, power output,
and c7linder teacoeratures. The engine was operated with tmospheric
inlet pressure inaasmuch as supercharging facilities were not
available.
Strain Gages and Circuit Diagram
The strain gages used, were attached by means of Bayelite BC-
6035 cement. All gages were of 120-ohm nominal roeistanco with a
strain-seonsitive area of 1/8 9by 1/3 inch square for each gage. The
strain wag measured by four strain gages, which were mounted on the
straincd me'dber closely adjacent to each other at the desired loca-
tions. (See fig. 1(a).) The strain-sensitive filaments of all four
strain gages wore orientated in the direction in which it was desired2
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Dutee, Francis J.; Phillips, Franklyn W. & Calvert, Howard F. Operating stresses in aircraft-engine crankshafts and connecting rods 2: instrumentation and test results, report, August 1945; (https://digital.library.unt.edu/ark:/67531/metadc61897/m1/3/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.